Certain surgical procedures require the surgeon to perform delicate operations on tissues within the body that are moving or otherwise unstable. For example, a large and growing number of surgeons are routinely performing successful coronary artery bypass graft surgery on the beating heart. In a typical coronary artery bypass graft (CABG) procedure, a blocked or restricted section of coronary artery, which normally supplies blood to a portion of the heart, is bypassed using a source vessel or a graft vessel to re-establish blood flow to the artery downstream of the blockage. This procedure requires the surgeon to create a fluid connection, or anastomosis, between the source or graft vessel and arteriotomy or incision in the coronary artery. Forming an anastomosis between two vessels in this manner is a particularly delicate procedure requiring the precise placement of tiny sutures in the tissue surrounding the arteriotomy in the coronary artery and in the source or graft vessel so that the two may be sutured together.
To ensure that the sutures may be placed with the required accuracy and precision to yield an anastomosis having long term patency, a number of devices have been developed to stabilize a portion of the heart in the vicinity of the target coronary artery. The vast majority of devices suitable for successfully stabilizing the beating heart use either compression or vacuum, or both, to engage and immobilize a portion of cardiac tissue, preferably along opposite sides of the target artery. Devices configured to use a compressive force to stabilize a surgical site on the beating heart can be found, for example, in U.S. Pat. No. 5,894,843 to Benetti et al. Examples of devices configured to use negative pressure or vacuum to stabilize or to assist in stabilizing cardiac tissue are described, for example, in U.S. Pat. Nos. 5,727,569 to Benetti et al. and 5,836,311 to Borst et al.
Although some stabilization devices reduce or eliminate the motion of the heart at the surgical site or target artery, visualization or presentation of the target artery, and more specifically the arteriotomy to which a vessel will be anastomosed, could be improved in certain surgeries. While a properly stabilized vessel will usually exhibit acceptable visualization, some operations and tissue geometries can distort the tissue surrounding the coronary artery or the coronary artery itself in a manner which complicates the completion of the anastomosis. For instance, excessive pushing on the cardiac tissue along each side of the coronary artery may tend to flatten the target artery top to bottom while pulling may tend to compress the target artery side to side as tissue is pulled higher than the target artery. In other instances, the target coronary artery is not conveniently located along the surface of the myocardium, but instead is partly or completely covered by fat or other tissue. In such cases, the stabilization forces alone can do little to optimize the visualization and presentation of the target artery.
The presentation of the target vessel and the arteriotomy is a significant factor in eliminating anastomotic errors which may cause vessel damage or a less than optimal anastomosis which may lead to failure of the anastomosis. When the arteriotomy is not optimally presented, there is a higher likelihood of incurring a surgical error in the formation of the anastomosis. To suture an anastomosis the surgeon generally works his needle from the inside vessel wall to the outside of the vessel wall. If the vessel is flattened, for example, it becomes more likely for the surgeon to accidentally catch the back wall of the vessel with the curved suture needle as the suture is placed in the tissue surrounding the arteriotomy. When the vessel is compressed side to side, it becomes more difficult to catch only the desired side of the arteriotomy without also catching the other side.
When the edges of the arteriotomy are not presented as desired, the surgeon may be required to manually manipulate the target artery using forceps or the like. The surgeon must be careful to only manipulate the vessel at the outside edges of the incision as manipulation to the interior of the vessel wall may cause damage to the soft intimal layer of the vessel leading to scarring and often late restenosis. Most often, the surgeon will try to only manipulate the tunica adventitia or outer coat of the vessel using forceps or other suitable instrument to present the arteriotomy in a manner which allows an accurate placement of each suture in the vessel from the inside out.
Even in the best of circumstances this manual manipulation of the vessel to facilitate each suture placement is tedious, time consuming, and increases the likelihood of vessel damage. This problem will become even more magnified as surgeons move to manual, computer-assisted, and robotic endoscopic procedures in which the surgeons will be attempting to complete anastomotic procedures in remote and difficult places. Delicate manipulation of the vessel walls while suturing becomes increasingly difficult as the surgeon becomes further removed from the surgical site by longer instruments, the size of the surgical site decreases leaving inadequate space to accommodate multiple instruments and the access incisions become smaller thus limiting instrument maneuverability.
In view of the foregoing, it would be desirable to have methods and devices which provide stabilization of the surgical site and target coronary artery and also provide favorable presentation of the edges of the arteriotomy so that manual manipulation of the vessel itself is reduced or eliminated. It would further be desirable to have stabilization and presentation devices which are adaptable to anatomical variations to aid in exposure of intramyocardial vessels and provide optimal vessel presentation over a wide range of operating conditions.